Preheat the oven to 375 degrees F. Line a baking sheet with parchment paper.
In a small bowl, whisk together the eggs, mustard and a splash of water until smooth; add salt, pepper, and Italian seasoning. Set aside.
Sprinkle flour over a clean work surface and roll out puff pastry to a 10 by 14 inch rectangle. Position puff pastry so that one side the shorter edge is closest to you.
Evenly spread Parmesan cheese over the top half of the dough. The fold the bottom half up over the top half to encase the cheese between the sheets of pastry. Gently roll the dough to seal up edges.
Cut the dough into 12 equal strips.
Carefully, cut each piece of Prosciutto in half lengthwise. Place each strip onto a piece of pastry. Carefully twist the pastry and Prosciutto together and place on prepared baking sheet.
Press down the ends of the pastry to baking sheet.
Brush the twists with the egg wash and sprinkle with sesame seeds, poppy seeds (I used both), and Italian seasoning.
Bake until the pastry is golden brown, 12 to 15 minutes. Remove the baking sheet to a rack and let cool for 5 minutes before removing.